UPDATED 10:24am: The controversial decision to allow an abattoir to dump their waste in a Christchurch river, is being met with disgust.

ECAN's independent commissioners have allowed Silver Fern Farms a five year emergency consent - with stringent terms and conditions.

The commissioners say they gave little weight to a petition bearing thousands of signatures against the move, because expert evidence shows the effect would be 'no more than minor.'

Despite impassioned protests from locals and a lengthy hearing process, they’re now able to dump waste into the Waimakariri River in rare flooding events when the city’s wastewater system is overloaded.

Open water swim instructor Daniel Abel says the report fails to mention the impact on other river users.

Silver Fern Farms delighted

Silver fern Farms is delighted ECAN's independent commissioners understood their need for an emergency consent.

CEO Dean Hamilton says they have the utmost respect for community values regarding water quality, in fact they share them.

He says he hopes they never have to use the consent, but the decision gives staff peace of mind that their jobs are safe during rare emergency floods.